Programmable switching type welding power sources have been developed for providing controllable electrical voltage and/or current waveforms to a welding process, an example of which is presented in Blankenship U.S. Pat. No. 5,278,390 incorporated by reference herein. The power source of this Blankenship patent and other welding power sources sold by The Lincoln Electric Company of Cleveland, Ohio provide precise waveform control by which a welding signal waveform can be tailored or customized for the exact conditions of a given welding application. This waveform control technology has been a major advancement of the welding arts generally, enabling optimization of welding processes. In order to implement and control advanced welding processes, substantial knowledge and experience may be needed to select a suitable welding waveform having several control parameters to produce an optimum welding process, and power source control apparatus has been developed for use with electric arc welders that have real time current/voltage waveforms developed by welding engineers to optimize the welding process performed in the field.
As shown in Blankenship U.S. Pat. No. 5,278,390, a microprocessor based controller is used, by which an operator can select from a number of predefined welding waveforms by merely using one of several overlays. By using a known template for the controller, an operator selects a welding waveform having the desired control parameters especially developed by a skilled welding engineer for a selected weld process. This successful controller had a certain amount of adjustability in the field; however, such on-site adjustments were limited. Mass production use of arc welders has created a demand for the ability to conveniently adjust certain control parameters of the welding waveform in the field, especially when the welding process conditions are different than what is used in designing standard waveforms shipped with the welders (such as cable length, shielding gas and welding wire). Thus, there was a need for a controller to be used with switching type welding power sources, where the controller can process a desired waveform that is adjusted interactively at the manufacturing site so the waveform is optimized for welding conditions and welding requirements for the job.
To fill this need, an electric arc welder was developed with a microprocessor based controller for the specific arc welder, as generally shown in Hsu U.S. Pat. No. 6,002,104 incorporated by reference herein. This Hsu welder has a switching type power supply for creating a welding cycle, with a real time current waveform constituting several control parameters by rapidly switching a D.C. current in a controlled fashion by a pulse width modulator. This patented controller has been used with various switching type power supplies, wherein Hsu U.S. Pat. No. 6,002,104 illustrates a down chopper power supply for simplicity. In practice, any type of switching power source, such as a pulse width modulated inverter type power supply along or in combination with other power conversion stages, can be controlled according to the principles set forth in Blankenship and Hsu.
FIG. 1 shows a welding system 2 with a switching type power source 4 and an automatic wire feeder 6 having a welding torch 8 coupled thereto via a torch cable 10 through which power and welding electrode wire are provided to a welding operation (not shown), where power source 4 is generally of the type shown in the above Blankenship and Hsu patents and as sold by the Lincoln Electric Company under the trademark POWER WAVE and feeder 6 can be one of the POWER FEED line of wire feeders sold by Lincoln Electric. In accordance with the teachings of Hsu U.S. Pat. No. 6,002,104, a portable laptop computer 12 is coupled to a communications port 14 of power source 4 using a serial communications cable 16, and a template or predefined waveform is displayed on a display screen 12a of computer 12. An operator (not shown) uses a keyboard 12b and/or a mouse 12c of computer 12 to make desired changes to the waveform or associated values rendered on display 12a and the updated waveform information is sent to power source 4, which implements the changes to the internal waveform controls therein.
The microprocessor based controller of this Hsu patent provided an operator with a displayed waveform to be processed by the power source 4 under the direction of the patented controller, as well as a keyboard 12b and/or mouse 12c for adjusting the waveform to generate a new waveform having the desired control parameters. A predefined waveform was first displayed, such as a current/voltage/power/RMS current/Joules/Travel speed vs. time graph, and a manual adjustment of the predefined waveform was performed interactively on a waveform display screen 12a using keyboard 12b and/or mouse 12c. In this manner, a new current waveform was exhibited on the display screen 12a. A pulse width modulator (not shown) of the switching power source 4 was controlled in accordance with the newly created waveform to cause the power source 4 to generate a welding cycle with the real time output corresponding to the new waveform on the waveform screen 12a. In this fashion, if a change was desired for a control parameter of the exhibited waveform, the waveform itself was modified visually by the operator using the mouse 12c and/or keyboard 12b of computer 12 connected to the welding system 2; where the interactive waveform modification of Hsu U.S. Pat. No. 6,002,104 was novel to the welding field and was implemented by including a JAVA virtual machine with a welder control application program or an applet running within a browser in JAVA language.
The microprocessor system of Hsu U.S. Pat. No. 6,002,104 included hardware with a first interface for an interactive display screen 12a and a second interface for a mouse 12c or keyboard type data entry device 12b for changing the displayed waveform prior to the waveform being transferred via cable 16 for providing control parameters to the welder 4, where the same communication channel was used to input operating parameters from the welder 4. When the operating parameters from welder 4 were inputted to computer 12, a separate “scope” application program in JAVA language was selected and implemented, whereby display 12a was converted from a waveform editor to an oscilloscope display for reading parameters from the welder 4 and for displaying these parameters as a soft oscilloscope on display 12a. 
In the prior art electric arc welder patented in Hsu U.S. Pat. No. 6,002,104, the processing logic was fixed and inflexible so that only certain types of waveforms pre-built into the program could be processed. For instance, a wave shape template was selected for display and manipulation, wherein the basic aspects of the template were fixed logic. Thus, the welder with a JAVA virtual machine could only select fixed templates for processing of specific welding waveforms, with limited ability to select from a memory location certain data and to display this as a waveform in a manner to change the behavior of the waveform template. In the prior art unit, the weld program compiled as object code or bytecodes was fixed to manipulate a fixed waveform logic.
Hsu U.S. Pat. No. 6,700,097 provided improvements, in which a series of script language files written by script language presented waveforms graphically from a subset of parameters, constraints and display characteristics of the parameters. By using the script language or script files, the user variables and graphic constraints were directly processed by a graphic user interface (GUI) computer platform including a JAVA virtual machine, and the relationship of the user variables were converted to data understood by the welder. As a result, the patented improvements of Hsu U.S. Pat. No. 6,700,097 provided a user friendly programming digital welding system using script to draw any waveform, rather than an operating program with pre-built waveforms. In this Hsu patent, the welding waveform script file was compiled into a JAVA object code in the form of bytecodes, which were then processed at run time by the main operating JAVA program, wherein the controller program was fixed, stable, and independent of the logic of each welding process. Hsu U.S. Pat. No. 6,717,108 provides waveform design methods to ensure that the waveforms conform to a desired implementation of a welding process. Another improvement was provided in Hsu U.S. Pat. No. 6,734,394, in a patented system for creating an actual welder output waveform via a waveform generator, with a display and customizing screen to design a commanded waveform for processing by the waveform generator. The above presents the general state of waveform control technology and the design of welding waveforms forming a background to the present invention.